Told in true Seanchai fashion, The Other of One is an Irish fantasy about a boy named William Muldoon who is summoned to a mythical world underground. The wondrous realm of Lythiann. There he meets a community of Imps who are seeking refuge from a Wrythunn most foul, Drevol Briggun. Being the reincarnation of the only other Wrythunn in existence who has the potential to confront Briggun's power, it is up to William to assassinate him. For not only is Lythiann under threat, but his own world is too..."

After finding his home in ruins and its villagers abducted by the infamous Shadows Guild, William returns to the land of myth to rescue them, only to make the shocking discovery that this is no longer the Lythiann he remembered. Nor is he the same person he once was.